Extrusion press for multiple tube configurations and the like



Dec. 5, 1967 Filed March 5, 1964 G. W. SIBLER ON PRESS FOR MULTIPLE TUBE IGURATIONS AND THE LIKE 8 Sheets-Sheet l INVENTOR. GOA-W75? W. 5/5152 Dec. 5, 1967 Filed March 5, 1964 8 Sheets-Sheet 2 88 INVENTOR. GUI/V715? W. 5/515? BY ff- 1% M Dec. 5, 1967 G. w. SIBLER 3,355,927

EXTRUSION PRESS FOR MULTIPLE TUBE CONFIGURATIONS AND THE LIKE Fil 1964 8 ShGGtS-Sht 5 ed March 5,

INVENTOR. GUL /V767? W 5/515? Airmen/fr.

Dec. 5, 1967 G. w. SIBLER 3,355,927 EXTRUSION PRESS FOR MULTIPLE TUBE CONFIGURATIONS AND THE LIKE Filed March 5, 1964 8 Sheets Sheet 4 INVENTOR. Gui/Wm w. S/BLEA 22,, M Arron 5X Dec. 5, 1967 G. w, SIBLER EXTRUSION PRESS FOR MULTIPLE TUBE CONFIGURATIONS AND THE LIKE 8 Sheets-Sheet 5 Filed March 1964 I NVEN TOR.

4 Tram/A Dec. 5, 1967 G. w. SIBLER EXTRUSION PRESS FOR MULTIPLE TUBE I CONFIGURATIONS AND THE LIKE Filed March 5, 1964 8 Sheets-Sheet 6 V INVENTOR. 6054 75F W. 3/52 5,?

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ATTOf/Yf/ Dec. 5, 1967 G. W. SIBLER ION PRESS FOR MULTIPLE TUBE INVENTOR. 605 N 727? W. .S/BLE/P BY Dec. 5, 1967 G w. SIBLER 3,355,927

EXTRUSION P RESS FOR MULTIPLE TUBE CONFIGURATIONS AND THE LIKE Filed March 5, 1964 8 Sheets-Sheet 8 United States Patent 3,355,927 EXTRUSION PRESS FOR MULTIPLE TUBE CONFIGURATIONS AND THE LH(E Guenter W. Sibler, Media, Pa., assignor to Baldwin-Lima- Hamilton Corporation, Philadelphia, Pa., a corporation of Delaware Filed Mar. 5, 1964, Ser. No. 349,575 Claims. (Cl. 72-461) This invention relates to an extrusion press and, more particularly, to a direct or indirect extrusion press for extruding multiple tube configurations and the like.

Heretofore, it has been conventional in the production of heat exchangers and the like to manufacture tubes separately and join one end of the tubes to a header. Such procedure was necessitated by the desire to have accurate control over wall thicknesses of the tube, and the lack of any satisfactory extrusion press capable of extruding a multiple tube configuration in a manner so that the tubes are closed at one end and integral at the other end with a common header. This desirable configuration is attainable by the apparatus of the present invention.

In order for the extrusion press of the present invention to be able to produce multiple tube configurations, the apparatus is structurally interrelated in a novel manner. Preformed billets are provided from which the tubes will be extruded and into which the mandrel will extend prior to commencement of the extrusion process. Also, the piercers supported by one end of the mandrel are therefore capable of being as small in length as possible so as to provide piercers which are rigid and likewise enable the wall thickness of the tube configurations to be as accurate as desired.

The apparatus of the present invention produces a directed and controlled volume flow of the billet during the extrusion process. All metals including copper alloys and steels can be extruded by the apparatus of the present invention into relatively complex shapes which may be symmetrical with respect to their longitudinal axis, if desired. A homogeneous metallic structure is provided by the apparatus of the present invention with smooth grain flow provided at joints and at billet radii. Heretofore, the joints between headers and tubes for high-grade heat exchangers frequently failed due to electrolytic corrosion resulting from the joining of different metals, as in the case of brazed or rolled joints. The apparatus of the present invention will enable the header and tube configuration to be made from a single material such as aluminum, which could not be manufactured heretofore.

It is an object of the present invention to provide an extrusion press for extruding multiple tube configurations and the like.

It is another object of the present invention to provide apparatus for extruding multiple tubes integral at one end with a header.

It is another object of the present invention to provide an extrusion press for extruding a plurality of tube-like configurations while providing for controlled volume flow and smooth grain flow.

It is another object of the present invention to provide a novel method of extruding multiple tube-like configurations.

Other objects will appear hereinafter.

For the purpose of illustrating the invention, there are shown in the drawings forms which are presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown. I

FIGURES 1a and 1b are a longitudinal sectional view of direct extrusion apparatus in accordance with the present invention.

FIGURES 2-5 are longitudinal sectional views show- ICC ing the position of the components in FIGURES 1a and lb during various stages of extrusion in accordance with the present invention.

FIGURE 6 is a partial enlarged sectional view of an extrusion produced by the apparatus in FIGURES 1-5 inclusive.

FIGURE 7 is a sectional view of a heat exchanger which can :be produced from the extruded tube-like configurations produced by the apparatus in FIGURES 1-5 inclusive.

FIGURES 8a and 8b are a longitudinal sectional view of apparatus in accordance with another embodiment of the present invention.

FIGURE 9 is a sectional view taken along the line 9-9 in FIGURE 8b.

FIGURES 10-12 are sectional views showing the components of the apparatus in FIGURES 8a and 8b in various positions during the extrusion process.

FIGURE 13 is a plan view of the die in FIGURES 10-12.

FIGURE 14 is a sectional view taken along the line 1414 in FIGURE 13.

FIGURE 15 is an end View of an extruded product produced by the apparatus in FIGURES 8-12.

FIGURE 16 is a view taken along the line 16-46 in FIGURE 15.

FIGURE 17 is an end view of the: product in FIG- URES 15 and 16 which has been machined.

FIGURE 18 is a sectional view taken along the line 1818 in FIGURE 17.

FIGURES 19-22 are longitudinal sectional views in accordance with another embodiment of the present invention illustrating the indirect extrusion process during various positions of the components.

FIGURE 23 is a partial end view of the piercer head in FIGURES l-5.

Referring to the drawing in detail, wherein like numerals indicate like elements, there is shown in FIG- URES 1a and 1b an extrusion apparatus designated generally as 10. It will be obvious to those skilled in the art that FIGURE 11; is the lefthand end of the apparatus illustrated in FIGURE 1a.

The extrusion apparatus 10, as illustrated, is somewhat diagrammatic and includes only the components necessary to understand the present invention. Thus, many conventional components are not shown. The apparatus 10 includes a bed plate 12 having a container housing 14 at one end. The housing 14 is provided with a container 16.

A die 18 having a removable insert is juxtaposed to the opening in the container 16 and supported in a conventional manner by a die holder 20.

A main cylinder 22 is supported on and connected to the bed plate 12. The main cylinder 22 is preferably of the type shown in US. Patent 2,924,075, and reciprocally receives therein a main ram 24- of the ram assembly 23. Motive fluid may be introduced into the main ram chamber 26 by way of passageway 28, auxiliary chamber 32 and inlet 34, as shown more clearly in FIGURE lb. The main ram 24 is provided with a hollow cylindrical extension 30 which is of sufficient length so as to extend into the connector housing 36. A seal is provided between the extension 30 and a mandrel 38 reciprocally dis posed therewithin. An adjustable limit stop 40 is provided at the terminal end of the mandrel 38 exterior of the housing 36.

A liner 42 is provided within the main ram 24. The mandrel 38 extends into the liner 42 and has a piston 44 fixedly secured thereto within the liner 42. Passages 46 and 48 are provided for introducing motive fluid to opposite sides of the piston 44 as desired and selectively controlled by apparatus not shown. Passages 46 and 48 communicate with flexible conduits, not shown, by way of support member 52 which is a part of the ram assembly 23 and moves therewith.

A collar 54 is provided as a part of the ram assembly 23 and is removably coupled to the main ram 24. Collar 54 removably secures a pressing stem 50 to the header block on the main ram 24. A mandrel extension 58 is removably and adjustably connected to the free end of the mandrel 38. Extension 58 is smaller in cross section than the mandrel 38. Accordingly, a spacer 56 surrounds the extension 58. A piercer head 60 surrounds the remainder of the extension 58 and is removably and adjustably coupled thereto. Piercer head 60 and spacer 56 are of substantially the same diameter and have a cross sectional area which, when added to the cross sectional area of extension 58, equals the cross sectional area of mandrel 38.

A plurality of short, stubby piercers 62, 64 and 66 are provided. Piercers 62 and 66 are removably coupled to the piercer head 60 such as by a threaded connection. As shown more clearly in FIGURE 23, the piercers 62 and 66 are preferably teardrop-shaped in cross section at their base or root where they are coupled to the piercer head 61 The terminal ends of the piercers 62 and 66 are round when extruding hollow cylindrical tubes. The apex of the teardrop points toward piercer 64. The teardrop configuration aids in preventing voids or other defects in the metal flowing around piercers 62 and 66 toward piercer 64.

The piercer 64 may be of the same diameter and cross sectional configuration as piercers 62 and 66. As illustrated, piercer 64 is larger in cross sectional configuration than piercers 62 and 66. Piercer 64 extends through a hole axially disposed in the piercer head 60 and rests on a shoulder on the latter. The leithand end of piercer 64 is threadediy coupled to the end of extension 58 whereby contact between the shoulder on piercer head 60 and the piercer 64 retains the piercer head 60 on the extension 58.

Extrusion in accordance with the apparatus of the present invention is preferably effected with a preformed billet having an axially disposed cavity 72. A dummy block '70 will be provided between the end of the stem 50 and the end of the billet 68. The end wall 74 of the billet 68 has a thickness which is approximately fifty to seventyfive percent of the exposed length of the piercers 62-66. The length of the piercers is substantially shorter than piercers conventionally used and is designed so as to pierce the wall 74 and initiate extrusion of closed-end tube-like configurations.

The die 18 is preferably provided with a removable insert 76 having die openings related to one another in the desired pattern for the tube-like configurations to be extruded. The die openings will correspond in number to the number of piercers and are in line therewith. As illustrated more clearly in FIGURE 5, the apparatus is structurally interrelated in a manner for simultaneously extruding tubes 73, 80 and 82 which are closed at one end and integral at the other end with a common header 84. The shape of the header 84 is in general determined by the configuration of the end face of the die 18 and the piercer head 60. By having controlled radii on the piercers and on the die insert, the tubes having a common header will be provided with controlled radii S6, 88 and 90, while at the same time being part of a product having uniform grain flow. The header 84 may be subjected to subsequent machining operations as desired.

The operation of apparatus 10 is as follows:

A preformed billet 68 having a central cavity 72 may be produced in accordance with any conventional method. The billet 68 is introduced into the container 16 and a dummy block 70 is placed therebehind. Thereafter, the ram asesmbly 23 is reciprocated to the right until the elements assume the position illustrated in FIGURE 2. Thereafter the mandrel 38 is reciprocated to the right by the introduction of motive fluid through passage 46 for actuating movement of piston 44 to the right in FIGURE 1a. When the mandrel 38 reaches the position so that its 4 extension 58 and the piercers 62-66 assume the position illustrated in FIGURE 3, the mandrel 38 is hydraulically locked in this position with the main ram 24. See FIG- URE 1a.

As illustrtaed in FIGURE 3, partial piercing of the wall 74 takes place. Thereafter, the main ram 24, together with the mandrel 38, is moved to the right in FIGURE 4 starting individual plug extrusions which continues until the tips of the piercers 62-66 advance into the die cavities in the die insert 76. When the last-mentionel condition has been attained, the mandrel 38 is prevented from further movement to the right in FIGURE 4 by its limit stop 40. See FIGURE 11).

Continued movement of the main ram 24 to the right in FIGURES 4 and 5 results in extrusion of the closed end tubes 78-82. When the main ram 24 has completed the stroke to the right in FIGURE 5, there is provided the common header 84 integral with the tubes 78-82. This completes the extrusion process, leaving the header 84 for further machining if desired.

For removal of the extruded product, the die holder 24) may be moved to the right. Thereafter, the extruded product may be pushed out to the right in FIGURE 5 by the main ram 24. Thereafter, the split die insert 76 should be separated and removed and the die holder separated from the extrusion.

The integral tube-like configurations and header may be further machined and utilized in the construction of a heat exchanger, such as the heat exchanger designated generally as 92 in FIGURE 7. Heat exchanger 92 includes a plurality of outer tubes 94a, 94b, 940 closed at one end and integral at the other end with a common header 96. Header 96 and heat exchanger body are removably connected to a support 98 with the tubes extending through an opening in the support 98.

A plurality of tubes 166a, 1G6b and 106C are provided with a common header 168. The end of the tubes 1116a, 1061? and 106C remote from the header 198 is constructed, such as by cutting, so as to be open. It will be noted that the tubes 106a, 106i) and 106c are smaller than and extend into the corresponding tubes 94a, 94b and 940.

The header 108 may be removably coupled to a shoulder in the heat exchanger body 106. Body 100 may be provided with a removable cover plate having an inlet 102 and an outlet 104. Outlet 104 is in communication with the tubes 94a, 94b and 940, whereas the inlet 102 is in communication with the tubes 106a, 1061) and 106C. Accordingly, fiuid may flow through the heat exchanger 92 in the direction of the arrows. Thus, it will be seen that the heat exchanger 92 may be constructed of a minimum number of parts and assembly of the same accomplished in a manner which is simple and easy to service. At the same time, the heat exchanger 92 may be constructed of materials which are not otherwise capable of being used for constructing heat exchangers due to the corrosive action at the joints between the tubes and the header.

In FIGURES 8-14, there is illustrated another embodiment of the present invention designated generally as 112 and adapted to produce the extruded product in FIGURES l5-18. The extrusion press 112 is substantially identical with extrusion press 10 except as will be made clear hereinafter. Accordingly, corresponding structure in the presses 10 and 112 are provided with primed numerals in press 112.

The extrusion apparatus 112 includes a hollow cylindrical mandrel 114 slidably receiving an extrusion stern 116. As shown more clearly in FIGURE 8b, the lefthand end of the ram extension 30' is integral with a terminal member 118. Terminal member 118 is coupled to connector member 120 by a plurality of rods 122. The connector member 120 is adjustably connected to the lefthand end of stem 116. Hence, ram 24' and stem 116 move together as a unit.

The lefthand end of the mandrel 114 is provided with an adjustable limit stop 40' which cooperates with the connector housing 36 in the same manner described above. A carriage 124 is removably coupled to the lefthand end of the mandrel 114. The carriage 124 is rollingly supported by the bed plate 12'.

A piston 126 is coupled to the mandrel 114. The piston 126 is disposed within the main ram 24, and passageways are diagrammatically illustrated for supplying motive fluid from flexible conduits 128 and 130 to opposite sides of the piston 126 for selective reciprocation of the same.

A cylindrical extension 132is adjustably and removably coupled to the righthand end of the mandrel 114. A plurality of piercers 134 are threadably connected to the end face of the extension 132 at spaced points therearound, whereby the piercers are disposed in the form of a circle;

A preformed billet 136 is provided for use with the extrusion press 112. Billet 136is provided with a cavity 138 which is concentric with the billet 136 and adapted to receive the annular mandrel extension 132. Billet 136 is also provided with a blind cavity 140 in its bottom. Cavity 140 is coaxial with the billet 136. Bottom wall 142 is provided with a thickness related to the length of the piercers 134 as described above in connection with press 10.

A die 144 is supported by a die holder 146 in alignment with the container 16. Die 144 is provided with a plurality of die inserts 148 at spaced points therearound so as to be in alignment with the piercers 134. The die inserts 148 are preferably split die inserts removably disposed within the die 144, and the number of such die inserts corresponds to the number of piercers 134.

The die 144 is provided with a centrally disposed tapered projection 15 adapted to enter the cavity 140 in the billet 136. The outer periphery of the die surface exposed to the billet is tapered inwardly at 152. Hence, surfaces 150 and 152 channel the flowing metal of the billet during the extrusion process outwardly and inwardly, respectively, toward the die inserts 148.

A ring-shaped dummy block 154 is provided and adapted to be juxtaposed to the end faces of the stem 50' and billet 136. A dummy block 156 is provided between the juxtaposed end faces of the stem 116 and billet 136. The billet 136 is adapted to be supported and positioned in alignment with the container 16' by a movable support 158. v

The operation of the extrusion press 112 is as follows:

Movable support 158 is actuated to position a preformed billet 136 and dummy block 154 in the position illustrated in FIGURE 10. Thereafter, the main ram assembly 23 is actuated to the right in FIGURE to move the billet 136 into the container 16. Thereafter, the mandrel 114 is actuated to the right in FIGURE 11 so that the mandrel extension 132 enters the cavity 138 and the piercers 134 partially pierce the wall 142. Typical dimensional proportions are piercers 134 having a 78 inch OD and an exposed length of 3 inches and wall 142 of a non-ferrous billet being 2 inches thick. Thereafter, the extrusion process is identical with that set forth above.

Since the extruded tube-like configurations will be disposed in the form of a circle, the surfaces of the tapered projection 150 cause the metal of the billet 136 to flow radially outwardly toward the die cavities. Likewise, the tapered surface 152 causes the metal of the billet 136 to flow radially inwardly toward the die cavities. In this manner, there is produced a directed and controlled volume flow from the center part of the billet in relation to the flow from the outer part of the billet. It will be appreciated that the stem 116 moves to the right with the ram assembly 23 so that coaxial forces, disposed radially inwardly and radially outwardly of the cavity 138, are simultaneously applied to the billet 136. The extrusion process is terminated at a point whereby a plurality of 6 closed end tubes 160 are integral at one end with a header 162.

In FIGURES 15 and 16, there is illustrated a typical extruded product of the apparatus 112. Subsequent machining of the header 162 may include the provision of a channel 164 concentric with the location of the tubes 160, drilling of a central stepped hole 166, and exterior machining to provide a shoulder 168. The extruded product, as finished machined in FIGURE 18, can be utilized in heat exchangers or the like. A typical die for such extrusion is shown in FIGURE 13.

Thus, while extrusion press 10 is particularly adapted for extruding tube-like configurations integral at one end with a header member, with the tube-like configurations being in a line, the extrusion press 112 is particularly adapted for extruding tube-like configurations disposed in a circle and integral at one end with a header. The extrusion presses 10 and 112 are direct extrusion presses.

In FIGURES 19-22, there is illustrated an indirect extrusion press 170. Extrusion press is identical with extrusion press 112, except that press 170 is adapted for indirect extrusion.

Thus, extrusion presses 112 and 170 are identical ex cept as will be made clear hereinafter. Accordingly, corresponding structure in extrusion press 170 is provided with double primed numerals.

The container 16 and its housing 14" are not fixedly secured to the bed 12". Instead, the housing 14" is reciprocally supported by the bed 12". A die slide 172 is supported from a fixed upright support 174 on the bed 12". A split collar ring 176 is adjustably provided to support the die slide 172 on the support 174.

Die slide 172 is providedwith passages in line with and larger than the die openings in the removable die inserts. The support 174 is provided with a large opening 178 in line with and concentric with the passages in the die slides 172. Prior to extruding the billet 136", a removable spacer 180 is provided between the container housing 14" and a removable pusher sleeve 182 on the ram assembly 23". The operaton of the extrusion press 170 is identical with that described above except as will be made clear hereinafter.

As the ram assembly 23" moves to the right in FIG- URE 20, pusher sleeve 182 abuts against the spacer 180 which in turn abuts against the container housing 14". Accordingly, the entire housing 14", container 16" and spacer 180 moves to the right, while the billet 136" is stationary and extruded through the die 144". The end product corresponds to that illustrated in FIGURES 15 and 16.

Thus, in indirect extrusion the billet is stationary and the container moves with the ram assembly. In direct extrusion, the billet is moved while the container is stationary. The extrusion press 10 is readily adapted for indirect extrusion in the same manner that extrusion press 112 is adapted for indirect extrusion.

Thus, it will be seen that the present invention provides at least two extrusion presses capable of being used in direct or indirect extrusion processes for extruding a plurality of tube-like configurations. By stopping the extruding process before all of the material has been extruded, the tube-like configurations will be integral at one end with a header which can be subsequently machined and utilized in a variety of environments, such as in a heat exchanger.

The die inserts in the presses 10, 112 and 170 are preferably inexpensive ceramic die inserts which can be readily broken after a single use. Thus, it is contemplated that the die inserts are expendable. The piercers in each of the above-described embodiments are of the shortest possible length in order to avoid piercer deflection when the piercers are not arranged in the position concentric with the mass of the billet. Piercer deflection is undesirable since it effects tube sheet strength and tube spacing.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification as indicating the scope of the invention.

It is claimed:

1. Apparatus for simultaneously extruding a plurality of hollow configurations comprising a main ram assembly having a mandrel slidably supported therewithin, means for separately and selectively reciprocating the mandrel with respect to said assembly, means removably coupling a plurality of short piercers to one end of said mandrel, at least some of said piercers being teardrop-shaped in cross-section adjacent the point where the piercers are coupled to the mandrel, with the apex of the teardropshape pointing toward the longitudinal axis of the mandrel, a die having a plurality of die openings corresponding in number to the number of piercers, said die openings being in line with said piercers, means for reciprocating the mandrel to a position wherein the piercers extend into the die openings, means for locking the mandrel with the piercers extending into the die openings, and means for reciprocating the ram assembly while said mandrel is in its locked position.

2. A method of making an article having a plurality of hollow elements and a header comprising the steps of providing a preformed billet having a blind cavity extending from one end, positioning the billet in a container so that the closed end is juxtaposed to a die, moving a mandrel terminating in a plurality of axially extending short piercers into said cavity, causing said piercers to pierce deform the Wall at the bottom of said cavity by pressing portions of said wall into said die, extruding only a portion of said billet through said die to form a plurality of hollow elements integral at one end with a header, and removing said integral elements and header from the extrusion press as a unit.

3. A method in accordance with claim 2 including the further step of machining said header so that said header may be coupled to a supporting structure.

4. A method in accordance with claim 2 wherein said deforming and extruding steps are accomplished in a manner to form hollow extruded elements which are closed at their end remote from said header.

5. A method in accordance with claim 2 wherein said step of providing a preformed billet includes the provision of a billet having a blind cavity which is annular in cross section.

6. A method in accordance with claim 2 wherein said extruding step includes causing the billet to contact a centrally disposed tapered projection in said cavity and thereby causing the metal of said billet to flow radially inwardly and outwardly toward the piercers.

7. A method in accordance with claim 2 wherein said extruding step includes moving the container relative to the die.

8. A method in accordance with claim 2 wherein said step ofproviding a billet includes the provision of a billet in the form of a hollow cylindrical shell with a cavity having an internal cross-sectional area in excess of the cross-sectional area of the mandrel.

9. A method in accordance with claim 4, and the further step of opening the closed ends of the hollow extruded elements.

10. A method in accordance with claim 9, wherein said step of opening the closed end of the hollow extruded elements is performed by cutting off the closed ends.

References Cited UNITED STATES PATENTS 2,142,704 1/1939 Sparks 72- 261 3,063,560 11/1962 Edgecombe 72-261 FOREIGN PATENTS 842,188 6/1952 Germany.

RICHARD J. HERBST, Primary Examiner.

H. D. HOINKES, Assistant Examiner. 

1. APPARATUS FOR SIMULTANEOUSLY EXTRUDING A PLURALITY OF HOLLOW CONFIGURATIONS COMPRISING A MAIN RAM ASSEMBLY HAVING A MANDREL SLIDABLY SUPPORTED THEREWITH, MEANS FOR SEPARATELY AND SELECTIVELY RECIPROCATING THE MANDREL WITH RESPECT TO SAID ASSEMBLY, MEANS REMOVABLY COUPLING A PLURALITY OF SHORT PIERCERS TO ONE END OF SAID MANDREL, AT LEAST SOME OF SAID PIECERS BEING TEARDROP-SHAPED IN CROSS-SECTION ADJACENT THE POINT WHERE THE PIERCERS ARE COUPLED TO THE MANDREL, WITH THE APEX OF THE TEARDROPSHAPE POINTING TOWARD THE LONGITUDINAL AXIS OF THE MANDREL, A DIE HAVING A PLURALITY OF DIE OPENINGS CORRESPONDING IN NUMBER TO THE NUMBER OF PIERCERS, SAID DIE OPENINGS BEING IN LINE WITH SAID PIERCERS, MEANS FOR RECIPROCATING THE MANDREL TO A POSITION WHEREIN THE PIERCERS EXTEND INTO THE DIE OPENINGS, MEANS FOR LOCKING THE MANDREL WITH THE PIERCERS EXTENDING INTO THE DIE OPENINGS, AND MEANS FOR RECIPROCATING THE RAM ASSEMBLY WHILE SAID MANDREL IS IN ITS LOCKED POSITION. 